Dynamic misting control for outdoor condensers

ABSTRACT

A dynamic misting control system can supply water to a condenser coil in varying degrees. The control system can include a controller, flow regulator (e.g., pump or separate), and mist generator (e.g., spray nozzles or otherwise). The controller can read outdoor humidity and temperature and vary power to the pump accordingly. The controller can also compare temperatures of the condenser coil to the outdoor humidity and temperature in adjusting the voltage. This can include calculating a voltage based on a first temperature of a coolant supply line and a second temperature in a return line and comparing those temperatures to the outside temperature and humidity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority to provisionalapplication No. 62/852,967, titled “Adaptive, Responsive, DynamicBuilding Ventilation Control and Equipment Monitor,” filed May 24, 2019,and also claims priority to provisional application No. 62/852,968,titled “HVAC Compressor and Heat Pump Monitoring System with MistingSystem for Condenser Coils,” filed May 24, 2019, both of which areincorporated by reference in their entireties.

BACKGROUND

Energy necessary for heating and cooling accounts for nearly 50% of thetotal energy cost for homes and other small structures. HVAC coolingoptions for such buildings has largely been limited to air source heatpumps and air source air conditioners for most consumers. However, theenergy efficiency of air source heat pumps and air source airconditioners is dependent on the outdoor temperature and outdoorhumidity. Water source heat pumps and water source air conditioners,available for large buildings, mid-rise and high-rise buildings, aredesigned to improve energy efficiency in high humidity and hightemperature conditions. Unfortunately, the use of water source systemsis limited for low-rise buildings and residences because of the largecooling towers and mist sprayers required on such systems.

Climate scientists split the Earth into approximately five main climatezones: tropical, dry, temperate, continental, and polar. The UnitedStates Department of Energy (“DOE”) divides these zones into eightclimate regions: hot-humid, mixed-humid, hot-dry, mixed-dry, cold,very-cold, subarctic, and marine. Of these, the only DOE climate regionswith efficient cooling by air source heat pumps and air conditioners aremixed-dry, cold, very-cold, and subarctic. This is because air sourceheat pump and air source air conditioner-based low-rise-building HVACsystems lose efficiency in high outdoor air humidity and/or high outdoorair temperature conditions.

For at least these reasons, a need exists for an improved misting systemfor condenser coils.

SUMMARY

A monitoring system is described for air conditioning and heat pumpcondensers (collectively, called outdoor condensing units). Themonitoring system can include a controller that determines when to mistthe condenser unit and at what intensity level. The decisions can bebased on sensor information from compressor current sensors, compressorcoil temperature sensors, refrigerant pressure sensors, and a fan motorcurrent sensor, in an example.

The controller can be a microprocessor that monitors the control signalsfrom the air handler and thermostat to determine if the condenser unitis on. When the condenser unit is on, the controller can determine amist intensity based on environmental temperature, outdoor humidity,cooling loop liquid supply, and suction return line temperatures. Thesecontroller can use these factors to determine the optimal conditions to:a) open a solenoid valve simultaneously with compressor coolingoperation, b) regulate water flow to provide the optimal volume of watermist onto the cooling fins through the system.

In one example, the system can include mist generators, such as nozzles,for attaching to an outside condenser unit of an air conditioningsystem. The nozzles can be attached to a pump that receives a controlsignal specified by the controller. The controller can detect an outdoorhumidity level from one or more outdoor sensors. The controller can alsodetect that the condenser unit is on, such as by receiving heating andcooling calls from a thermostat.

In one example, the system can include ultrasonic mist generators withmist towers for attaching to an outside condenser unit of an airconditioning system. The mist generators can be attached to a flowregulator that receives water flow control signals specified by thecontroller. The controller can detect an outdoor humidity level from oneor more outdoor sensors. The controller can also detect that thecondenser unit is on, such as by receiving heating and cooling callsfrom a thermostat.

When the condenser unit is on and humidity and outdoor temperaturelevels meet thresholds, the controller can open a valve for supplyingwater to the pump. This can include opening a valve for a flow regulatorthat is part of the pump or attaches to the pump. The controller canadjust water flow rate based on the outdoor humidity level. This cancause the flow regulator or pump to move more or less water, dependingon the environmental factors that influence the need for the misting.The pump supplies water to nozzles attached to the condenser unitaccording to the control signal while the flow regulator supplies waterto the mist generators of the mist towers. In one example, the controlsignal is sent to the flow regulator, which is attached to the mistgenerators. In another example, the flow regulator is part of a pump andthe control signal can be a power level that adjusts pump speed.Although the pump is referred to in examples below, it is understoodthat a pump can include flow regulation and that a separate flowregulator can be used in other examples.

The misting system for condenser coils can include an irrigation waterfilter, self-priming variable speed medium pressure fluid pump, flowregulator, low-voltage water-controlling irrigation, and solenoid valve.The pump, the controller, mist generators and spray-nozzles can, in oneexample: a) attach to an air conditioner; b) control and regulatespecific quantity, angle and size of water particles (spray) to thecooling fins/coil; c) connect to a variety of water supplies. Thecontroller can extend equipment longevity and saves electricity bycausing a) decreasing air temperature near the condenser coil by mistcooling, b) increasing evaporative cooling of the condenser coil, c)facilitating rapid coolant conversion from gas to liquid in thecondenser coil, and d) optimizing compressor head pressure to cool bothfaster and more efficiently. The self-priming pump can draw water from apressurized or unpressurized supply-water and pump pressurized waterthrough the water filter and solenoid valve under control of themicroprocessor. The microprocessor can monitor the control signals fromthe air handler and thermostat along with environmental temperature andhumidity and cooling loop liquid supply and suction return linetemperatures to determine the optimal conditions to a) open the solenoidvalve simultaneously with compressor cooling operation, and b) turn onthe pump and regulate pump speed to provide the optimal volume of watermist onto the cooling fins through the system.

The system can deploy the right sized droplets at the right volume andspeed. This can be based on current humidity levels, ensuring that thecondenser is at the correct humidity. This can include dynamicallyvarying the volume and particle size based on the compressor, in anexample. The controller can ensure that the water is limited such thatit insulates the coil and makes it less useful.

To do this, the system can utilize a variable speed pump to providevariable pressure for the mist particles. The pump can be hooked up to ahose, such as a conventional garden hose in an example. In anotherexample, the water is filtered before entering the pump. In one example,an all-terrain vehicle (“ATV”) racing fuel pump can be repurposed foroperation with water based on outputs from the controller.

The controller can be a microprocessor that monitors the control signalsfrom the air handler and thermostat along with environmental temperatureand humidity and cooling loop liquid supply and suction return linepressures, compressor coil temperature, compressor and fan motor currentdraw to determine the function of the monitored components, to identifymalfunction of a monitored component, to monitor refrigerant pressure,and to identify refrigerant leaks. The system can report changes incomponent function and refrigerant pressure that require service via thewireless interface.

A monitoring system is described for air conditioning and heating airhandler (collectively, called indoor air handler units). The monitoringsystem can include a controller that determines when to sanitize theevaporator coil, drip pan, air handler and air stream and at whatintensity level. The decisions can be based on sensor information fromair handler current sensors, evaporator coil temperature sensors, and afan motor current sensor, in an example.

The controller can be a microprocessor that monitors the control signalsfrom the air handler and thermostat to determine if the air handler fanunit is on. When the air handler fan unit is on, the controller canactivate a UV sanitizer.

In one example, the system can include UV sanitizer panels for attachingto the inside of the air handler unit of an air conditioning system. TheUV sanitizer panels can be attached above and below the condenser coil.The UV sanitizer panels receive a control signal specified by thecontroller.

When the air handler fan unit is on, the controller can activate the UVsanitizer. A safety switch can ensure that the UV sanitizer does notilluminate when the air handler casing is open. This feature protectspeople from exposure to UV radiation during servicing of the airhandler.

The examples summarized above can each be incorporated into anon-transitory, computer-readable medium having instructions that, whenexecuted by a processor associated with a computing device, cause theprocessor to perform the stages described.

Both the foregoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the examples, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of an example method for misting control for anoutdoor condenser unit.

FIG. 2 is an example sequence diagram for misting control system at anoutdoor condenser unit.

FIG. 3 is an example system diagram of components for controlled mistingin an air conditioning system.

FIG. 4 is an example illustration of a condensing unit equipped withmisting components.

DESCRIPTION OF THE EXAMPLES

Reference will now be made in detail to the present examples, includingexamples illustrated in the accompanying drawings. Wherever possible,the same reference numbers will be used throughout the drawings to referto the same or like parts.

FIG. 1 is an example flowchart with stages performed by a controller foroperating a misting system. The misting system can be attached to anoutdoor condenser unit, which may be part of a heating, ventilation, andair conditioning (“HVAC”) system. The condenser unit can be part of anytype of air conditioning system, such as a heat pump system. Thecontroller can either be located indoors or mounted outdoors on thecondenser unit, in various examples. A pump can be mounted to thecondenser unit, along with a series of nozzles to mist the condensercoils. A water supply, such as a hose, can be attached to the pump.

At stage 110, the controller can detect an outdoor humidity level. Thiscan be based on outdoor sensor information from one or more sensors. Aswill be described, the controller can control the pump based on currenthumidity and temperature information. The controller can continuously orperiodically monitor humidity and temperature. In one example, thecontroller only monitors temperature and humidity when the condenser ison.

At stage 120, the controller can detect that the condenser unit is on.In one example, when there is a “cool on” signal from the thermostat,the controller can send requests for data to various sensors. Thesensors can respond with the latest measurements captured.Simultaneously, when a “cool on” signal is received from the thermostat,the controller can determine if the temperature and humidity of outsideair is appropriate for mist cooling of intake air and/or evaporativecooling of the condenser coil. To make this determination, thecontroller can compare condenser coil temperature to outdoor temperatureand humidity, as shown in Equation 1, below.

Condenser Coil Temperature (° F.)>Outdoor Temperature (° F.)+((%humidity−0.6)*100)+10   Equation 1

In one example, the controller can open a water supply valve at stage130 when the condenser unit is on and the outdoor sensor informationdictates. For example, if there is a “cool on” signal from thethermostat and outside air temperature and humidity meets therequirements of Equation 1, the controller can command the irrigationvalve solenoid to allow source water to flow to the fluid pump. Thecontroller can also turn on power to the fluid pump motor.

At stage 140, the controller can control the volume of water providedfor mist cooling of intake air and/or evaporative cooling of thecondenser coil. To do this, the controller can vary the voltage suppliedto the fluid pump motor, which change the speed at which the motor pumpswater. The controller can vary the pump power voltage in response tocoolant temperatures in the coolant evaporator suction return line andthe coolant liquid supply line in relationship to the outdoortemperature and outdoor humidity. Sensors in or on the suction returnline and coolant liquid supply line can supply sensor information usedby the controller to calculate the voltage level. In one example, thecontroller can use Equation 2, below to determine the voltage (V).

V=[(8+(ET−37)*0.30556]+[(LT−OT)*0.28947]−[(H−90%)*289.47368]  Equation 2

Where:

-   -   V=Pump Motor Supply Voltage (DC)    -   ET=Coolant Evaporator Line Temperature in ° F.    -   LT=Coolant Liquid Line Temperature in ° F.    -   OT=Outdoor Temperature in ° F.    -   H=% Outdoor Humidity

In one example, the controller can continuously adjust pump voltageuntil an off condition exists. The off condition can occur when there isno longer a “cool on” signal from the thermostat. Alternatively, the offcondition can occur when outside air temperature and humidity is nolonger appropriate for mist cooling of intake air and/or evaporativecooling of the condenser coil—such through use of Equation 1. When anoff condition exists, the controller can command the irrigation valvesolenoid to stop source water flow to the fluid pump and turn off powerto the fluid pump motor.

At stage 150, the pump supplies water to the nozzles according to thepower level (i.e., voltage supplied from the controller). The nozzlescan be part of a tubing loop or line that is attached to the condenserunit. The nozzles can spray the water such that a mist contacts thecondenser lines. This can help with the heat transfer between thecondenser lines and outdoor air.

The pump can variably operate between 50 to 160 psi operating pressure,depending on the voltage supplied from the controller. This can allowthe pump to range between 5 to 20 gallon per hour output fluid pump.

FIG. 2 is an example sequence diagram for controlling misting for acondenser unit. At stage 205, the controller can detect that the HVACsystem is on. This detection can be based on the controller monitoringcontrol signals from the thermostat in the HVAC system. For example, thethermostat can send heating and cooling calls. In some HVAC systems, acooling call causes condenser unit operation. In other HVAC systems,such as with a heat pump, the condenser can operate for heating andcooling calls. In another example, a sensor on a power line to thecondenser unit can allow the controller to determine the outdoorcondenser is on based on the voltage or current being supplied. Forexample, a current sensor can detect power flowing to the condenserblower.

In one example, if the condenser is on, the controller can begindetermining whether to mist the condenser coils and the relative amountof water to apply. As part of this, at stage 210, sensors can providehumidity and temperature information to a controller. The sensors canprovide both indoor and outdoor information, in an example. One or moreof the sensors can be part of a sensor package, in an example. A sensorpackage can include a microprocessor board with memory and I/Oconnections, a temperature sensor, a humidity sensor, and variousenvironmental sensors in an example. Alternatively, the system can usestandalone sensors that produce sensor information interpreted by thecontroller.

In this example, at stage 210 an outdoor sensor can indicate a lowhumidity level, such below 55%. Sensor information can also indicate theoutdoor air temperature, such as 85 degrees Fahrenheit.

At stage 215, the controller can send a signal to open the solenoidvalue and supply water to the pump. This signal can be based on theoperational status detected at stage 205 and the outdoor sensorinformation of stage 210. For example, Equation 1 or a similar equationcan be used to determine that outdoor air temperatures are high enoughin combination with the humidity to warrant misting. This can allow thecontroller to ensure that water is not wasted and that the condensercoils are not excessively wet, in an example.

When the valve is open, the controller can also set the pump rate bysupplying a voltage to the pump. In this example, at stage 220 thecontroller sends a voltage signal indicating a relatively high pumprate. This can be based, for example, on an outside temperature above 85degrees Fahrenheit with a humidity below 60 percent.

The controller can continue to monitor condenser operation and sensorinformation and adjust the misting operation accordingly. For example,at stage 225 the controller can detect that humidity has increased. Forexample, the humidity may rise to 90%. As a result, less mist may beneeded to keep the condenser coils sufficiently wet for increased heattransfer. This is because the evaporation of the mist can slow when theoutside air is already very humid. As a result, at stage 240 a lowervoltage can be sent to the pump, decreasing the water supply sent to thenozzles.

At stage 235, the controller can detect that the condenser is switchedto off. This can occur when the desired indoor temperature is met, andthe thermostat sends a signal to turn off air conditioning or end acooling cycle. The controller can detect this operational change in thesame manner as described for stage 205.

When the condenser is off, there is no need to continue misting thecondenser. As a result, the controller can send a command to close thevalve at stage 240. The controller can also send an “off” command to thepump, such as by ceasing to supply voltage, at stage 245. This candeactivate the pump and cause the nozzles to discontinue spraying miston the condenser coils.

The controller can detect when the condenser operational state changesback to “on,” such as at stage 255. The controller can again retrievethe most recent temperature and humidity sensor information, such as atstage 250. In this example, a 100 percent humidity can indicate thepresence of rain. Alternatively, temperatures approaching freezing canbe detected by the controller. In either case, the controller can send asignal to close the valve at stage 260 and turn off the pump at stage265. When rain exists, it can be wasteful to also mist the condensercoils and can also lead to excess moisture in the area of the condenserunit. Likewise, when cold temperatures exist, efficiency for heattransfer can fall to a level that nullifies practical advantages of themisting improvements. Preventing excess moisture in that scenario canbecome more important for purposes of preventing freezing of thecondenser coils.

Later, at stage 270, the controller can detect reduced humidity andhigher temperatures. In response, the controller can once again open thevalve at stage 275 and supply a medium level voltage at stage 280.

This process can continue indefinitely, generating substantialoperational cost savings for the HVAC system while avoiding issuesrelated to excess moisture at the outdoor air condenser.

FIG. 3 is an example system diagram of components for controlled mistingin an air conditioning system. In one example the control system can acontroller 310. In one example, the controller 310 can include amicroprocessor board with memory and input/output (“I/O”) connections(“COTS”). The controller can include custom hardware using COTScomponents, such as 24 volt AC to DC voltage converters, switches,relays, DC microprocessor controlled variable output DC converters, anda wireless communications interface. The controller 310 can read thevarious control lines of the HVAC system, read the data from sensors312, 314, 316, 318 and control relays on a relay board, in an example.

To determine if the condenser unit 350 is on, the controller 310 canreceive a signal from a thermostat 330 in an example. For example, thethermostat can send heating and cooling calls on various wires to theHVAC system. Those wires can be connected to the controller, in anexample, or to a wireless module that communicates with the controller.The thermostat 310 can send signals to the air handler 340, which inturn can communicate with the condenser unit 350.

The controller 310 can alternatively determine operational state bymonitoring signals for one or more of a mode control 342, blower control344, and compressor mode 346. Since an HVAC system typically uses 24volts AC and the controller can use DC voltage to operate, bufferingbetween the two environments can be handled by a custom circuit—onecircuit per HVAC line required to be monitored. In one example, thecontroller 310 only needs to detect the presence of 24 volts AC on acontrol line so an Optical Isolator (opto-isolator) is used to allow forthis detection without imposing a burden onto the HVAC system. Resistorson the AC side can allow for the opto-isolator to interface with theHVAC system while resistors and capacitors on the DC voltage side allowfor a steady output dependent on the state of the monitored HVAC line.The output on the DC voltage side is tied to an input on the processorboard so the system can read the output state.

The controller can operate a valve 320 and pump motor 322. To turn thevalve 320 on and off, the controller 310 can send a valve control signalto the valve 320. Likewise, the controller can vary the pump speed witha motor control voltage sent to the pump 322. The valve 320 can be a24-volt AC solenoid irrigation water valve with three-quarter-inch pipesize, in an example. The valve 320 can be attached to or integrated withpump 322. The assembly can include a three-quarter-inch water filter anda garden hose fitting, in an example. The pump 322 can include aself-priming variable speed DC voltage, high pressure, high gallon perhour (“GPH”), fluid pump, in an example. The pump assembly can includeboth the valve 320 and pump 322 and can be weatherproof in an example.The pump assembly can attach to a nozzle assembly or mist generator inan example.

The control system can control the irrigation valve 320 by applying orremoving 24 volts AC to the solenoid control lines. Similarly, thesystem controls power to the fluid pump 322 by applying or removingvarying DC power to the power lines of the fluid pump motor. Thesevoltages can be interrupted with a relay board, in an example.

To determine when and how to operate the valve 320 and pump 322, thecontroller 310 can receive sensor information from various sensors. Inone example, an Outdoor Air Quality (“OAQ”) sensor package 312 caninclude COTS components. The controller 310 can request data from theOAQ sensor package 312, and the OAQ sensor package can send sensorinformation related to temperature and humidity. The OAQ sensor packagecan include an array of sensors for detecting temperature and humidity.

In one example, a condenser coil temperature sensor 314 can provide thetemperature of the condenser coil. This sensor 314 can clamp onto thecondenser coil, in an example. To determine whether open the valve 320or in adjusting the pump 322 level, the controller can compare condensercoil temperature to a function output of the outdoor temperature andoutdoor humidity.

An evaporator line sensor 316 or coolant liquid supply line sensor 318likewise can allow the controller to adjust misting downward when theevaporator line is already beneath a coldness threshold. The controlsystem can use data from a combination of sensor arrays to determine if,when, and what volume of filtered water mist is appropriate to optimizeoperating efficiency for each HVAC operational cycle.

In one example, the controller 310 can connect to the internet and localinternet protocol (“IP”) network via a wireless communications interfacemodule installed in the Main Controller case. Internet connectivity canbe used for user interactions and system functions including but notlimited to the items in Table 1, below.

TABLE 1 Display Outdoor Air Temp and Humidity Display RefrigerantEvaporator Line Pressure Display Refrigerant Condenser Coil Temp DisplayRefrigerant Liquid Supply Line Pressure Display Compressor Current DrawDisplay Fan Current Draw Display Water Valve On/Off State Display FluidPump Speed/Voltage User Notifications Store, Display and Export OutdoorTemp and Humidity, Refrigerant Line Temps, Condenser Temp, Valve Stateand Fluid Pump Parameters over time Graph Outdoor Temp and Humidity,Refrigerant Line Temps, Condenser Temp, Valve State and Fluid PumpParameters over time Pause/Deactivate Automated Mist FunctionsCommunicate with other Natural Air E-Controls Products and ServicesSoftware Updates

In one example, the control system is designed to use water from bothpressurized and unpressurized filterable water sources common tolow-rise building and residential communities. The COTSthree-quarter-inch hose fitting of the COTS inline water filter providesconnection for supply water. The water filter screws into thethree-quarter-inch fitting of the COTS irrigation valve which controlswater flow to the connected self-priming variable speed fluid pump.Water leaves the pump through a COTS three-sixteenth-inch fluid linethat forms a loop terminating in a COTS auto drain valve. The COTS Teefittings and COTS mist nozzles/mist generators along the COTS fluid lineproduce the mist for mist cooling of intake air and evaporative coolingof the condenser coil.

The controller 310 can operate with an outdoor air quality (“OAQ”)sensor package. The Outdoor Sensor Package can include a processorboard, a temperature sensor and a humidity sensor. The data from thesensor array is combined by the on-board processor in the Air QualitySensor Package, evaluated for their validity then packaged intodata-packets and made available to the Main Controller via a four-wirecable using a common data protocol. Pull-up resistors on the data-linesallow for transmission over the wires at distances greater than 100feet. Sensor packages are powered by a common DC voltage regulatedpower-supply. Since the temperature and humidity sensors operates at alower voltage, a COTS DC voltage level shifter is utilized to regulatethe DC voltage supply to the voltage required by the gas sensor. Data toand from the gas sensor is buffered by the DC voltage level shifter. Anexample sensor array is shown in FIG. 8.

The controller 310 can operate according to settings on a mobileapplication or web interface in one example. For simplicity, the mobileapplication is discussed but the same concepts are possible for the webinterface. The mobile application can allow a user to set temperatureand humidity thresholds for powering on the misting, in an example. Themobile application can allow the user to also set misting intensity sothat the controller ramps up pump 322 speed according to a user-definedset of temperature and humidity thresholds.

The mobile application can also allow the user to view variousstatistics about the control system. For example, the mobile applicationcan have user-selectable options, including:

-   -   Display Outdoor Air Temp and Humidity;    -   Display Refrigerant Evaporator Line Pressure;    -   Display Refrigerant Condenser Coil Temp;    -   Display Refrigerant Liquid Supply Line Pressure;    -   Display Compressor Current Draw;    -   Display Fan Current Draw;    -   Display Water Valve On/Off State;    -   Display Fluid Pump Speed/Voltage;    -   User Notifications;    -   Store, Display and Export Outdoor Temp and Humidity, Refrigerant        Line Temps, Condenser Temp, Valve State and Fluid Pump        Parameters over time;    -   Graph Outdoor Temp and Humidity, Refrigerant Line Pressure,        Condenser Temp, Current Draws, Valve State and Fluid Pump        Parameters over time; and    -   Pause /Deactivate Automated Mist Functions.

The mobile application can also be set to control the misting systemaccording to US DOE climate regions, which can have different defaultthresholds for adjusting pump power.

In one example, the controller 310 can also activate an ultravioletsanitizer module 341 that sanitizes the evaporator coils of the airhandler. The UV sanitizer module 341 can be powered by a 240V A/C sourcein one example. The UV sanitizer module 341 can include two or three UVsanitizer illumination panels positioned inside the air handler tosanitize the surfaces of the evaporator coil, drip pan and air handlerwalls.

FIG. 4 is an example illustration of a condensing unit 400 equipped withmisting components. In one example, a pump housing 420 is mounted to thecondensing unit 400. The pump housing 420 can weatherproof the pump 322and valve 320, in an example. A water supply inlet 422 can be attachedto a hose or other water source.

A nozzle tube 430 can be attached to the pump 322 and the condenser unit400. The nozzle tube 430 can include multiple nozzles 432 for mistingpurposes. In this example, four nozzles 432 are provided, but otherconfigurations are possible. The nozzles 432 can be oriented to spraymist on condenser coils within the condenser unit 400. When the fan 440is on, the mist can be drawn in through vents 450 in the sides of thecondenser unit 400, in an example.

Additionally, controller housing 410 can house the controller 310. Thecontroller housing 410 can be installed on the condenser unit 400 orelsewhere, depending on the example. The controller can monitor functionof the outside compressor unit (e.g., AC or Heat Pump) in both coolingand heating cycles, in an example. As described above, the monitoringcan be based on an outdoor air temperature sensor and outdoor airhumidity sensor. In addition, the controller can utilize a currentsensor circuit to monitor fan and compressor motor operation and energyuse and determine that the operational state is on. The controller canalso use a pressure sensor to monitor refrigerant pressure andcompressor output. Further, the controller can utilize refrigeranttemperature sensors to monitor compressor output and coil efficiency.

The UV sanitizer system can be attached to an air handler unit, whichmay be part of the HVAC system. The air handler unit can be part of anytype of air conditioning system, such as a heat pump system. Thecontroller can be located indoors on or inside the air handler unit, invarious examples. UV sanitizer illumination panels can be mounted insidethe air handler unit above and below the evaporator coil(s). A safetyswitch is located at the access panel to deenergize the UV sanitizerillumination panel when the air handler access panel is open. Thecontroller can detect that the air handler fan is on. This can be basedon current sensor information from one or more sensors or on thedetection of a “fan on” signal from the thermostat. As will bedescribed, the controller can control the UV sanitizer. The controllercan detect that the air handler unit access panel is closed. In oneexample, there can be a safety switch that signals the controller thatthe access panel is closed. The controller can energize the UV sanitizerillumination panels.

This process can continue indefinitely, generating substantialoperational safety for the building occupants served by the HVAC systemwhile avoiding issues related to excess moisture at the air handler andducts.

Other examples of the disclosure will be apparent to those skilled inthe art from consideration of the specification and practice of theexamples disclosed herein. Though some of the described methods havebeen presented as a series of steps, it should be appreciated that oneor more steps can occur simultaneously, in an overlapping fashion, or ina different order. The orders of steps presented are only illustrativeof the possibilities and those steps can be executed or performed in anysuitable fashion. Moreover, the various features of the examplesdescribed here are not mutually exclusive. Rather any feature of anyexample described here can be incorporated into any other suitableexample. It is intended that the specification and examples beconsidered as exemplary only, with a true scope and spirit of thedisclosure being indicated by the following claims.

What is claimed is:
 1. A misting system co control signal mprising: mistgenerators for attaching to an outside condenser unit of an airconditioning system; a flow regulator coupled to the mist generators;and a controller that communicates with the flow regulator, wherein thecontroller performs stages comprising: detecting an outdoor humiditylevel; detecting that the condenser unit is on; opening a valve forsupplying water to the flow regulator when the condenser is on; andadjusting a control signal to the flow regulator based on the outdoorhumidity level, wherein the flow regulator supplies water to mistgenerators attached to the condenser unit according to the controlsignal.
 2. The system of claim 1, wherein detecting that the condenseris on includes receiving a signal from a thermostat.
 3. The system ofclaim 1, the stages further comprising: detecting an outside airtemperature by receiving information from a sensor; and whereinadjusting the control signal to the flow regulator is further based onthe outside air temperature.
 4. The system of claim 3, wherein thecontroller opens the valve based on calculating that a condenser coiltemperature is greater than a function of the outdoor temperature andoutdoor humidity.
 5. The system of claim 3, wherein the control signalto the flow regulator varies a water flow rate.
 6. The system of claim1, wherein the control signal is adjusted based on a first temperatureof coolant in a suction return line and a second temperature in a liquidsupply line, the first and second temperatures being weighted relativeto an outdoor temperature and the outdoor humidity.
 7. The system ofclaim 1, the stages further comprising sending a sanitation signal thatcauses an ultraviolet light panel in an indoor unit to sanitize anevaporator coil.
 8. A method for providing mist control for an outsidecondenser unit of an air conditioning system, comprising: detecting, ata controller, an outdoor humidity level based on outdoor sensorinformation; detecting, at the controller, that the condenser unit ison; opening a valve for supplying water to a flow regulator when thecondenser unit is on; and adjusting a control signal to the flowregulator based on the outdoor humidity level, wherein the flowregulator supplies water to mist generators attached to the condenserunit according to the control signal.
 9. The method of claim 8, whereindetecting that the condenser unit is on includes receiving a signal froma thermostat.
 10. The method of claim 8, further comprising: detectingan outside air temperature by receiving information from a sensor; andwherein adjusting the control signal to the flow regulator is furtherbased on the outside air temperature.
 11. The method of claim 10,wherein the controller opens the valve based on calculating that acondenser coil temperature is greater than a function of the outdoortemperature and outdoor humidity.
 12. The method of claim 10, whereinthe control signal causes a pump to vary a pump motor speed.
 13. Themethod of claim 8, wherein the control signal is adjusted based on afirst temperature of coolant in a suction return line and a secondtemperature in a liquid supply line, the first and second temperaturesbeing weighted relative to an outdoor temperature and the outdoorhumidity.
 14. The method of claim 8, further comprising sending asanitation signal that causes an ultraviolet light panel in an indoorunit to sanitize an evaporator coil.
 15. A non-transitory,computer-readable medium containing instructions for providing mistcontrol for an outdoor condenser unit, the instructions executed by acontroller to perform stages comprising: detecting, at a controller, anoutdoor humidity level based on outdoor sensor information; detecting,at the controller, that the condenser unit is on; opening a valve forsupplying water to a pump when the condenser unit is on; and adjusting acontrol signal to the pump based on the outdoor humidity level, whereinthe pump supplies water to mist generators attached to the condenserunit according to the control signal.
 16. The non-transitory,computer-readable medium of claim 15, wherein detecting that thecondenser unit is on includes receiving a signal from a thermostat. 17.The non-transitory, computer-readable medium of claim 15, the stagesfurther comprising: detecting an outside air temperature by receivinginformation from a sensor; and wherein adjusting the control signal tothe pump is further based on the outside air temperature, and whereinthe control signal is sent to a flow regulator that is attached to themist generators.
 18. The non-transitory, computer-readable medium ofclaim 17, wherein the controller opens the valve based on calculatingthat a condenser coil temperature is greater than a function of theoutdoor temperature and outdoor humidity.
 19. The non-transitory,computer-readable medium of claim 17, wherein the control signal to thepump varies a pump motor speed.
 20. The non-transitory,computer-readable medium of claim 15, wherein the control signal isadjusted based on a first temperature of coolant in a suction returnline and a second temperature in a liquid supply line, the first andsecond temperatures being weighted relative to an outdoor temperatureand the outdoor humidity.